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(11) | EP 1 522 893 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Illumination optical system and exposure apparatus having the same |
(57) An illumination optical system for illuminating an object surface using light from
a light source includes a condenser optical system (110) for directing the light from
the light source to the object surface (IS), wherein the condenser optical system
includes first and second optical systems, one of which forms a beam expander optical
system (120) for varying a diameter of incident light, the beam expander being adapted
to be movable as one element along an optical axis. |